12S power systems ideas and options

[Aeroplayin]

For those of you wanting to use the DM5335-189 in the new Extreme Flight MXS that should be available this year, the 22x10E Mejzlik will pull about 31 to 32 pounds (calculated) at between 7120 and 7250 RPMs. Using TimmyC's weight in place of the A60 on my Extra 300 setup, that could mean 13.6 pounds AU with a 2x 6S 4000mAh and just ballistic 293 Watts per pound, and 2.28 to 1 thrust to weight. Here the final chart for this motor with the various props tested.

 

[Enterprise]

Very cool data. I will plug in some comparisons to the a60-8s setup in you calculator when I get off the work merry go round. The hacker or 4330 setup looks like around 12oz lighter. I would think the 8s will spin the 21x10 and maybe the 22x10 as well and I would use 3300s probably. It will not be as ballistic, but should be lighter on the wing loading.

I will try to pick up the Hacker at Toledo as there was good pricing on them 2 years ago I believe at the esprit booth.

 

[Aeroplayin]

Thanks. I'm happy the way things are working out with the calculations. We also have an opportunity to firm up the pK values. Bryan will be happy to know that the PJN number is working it's way back to the value he likes to use when running setups through the PropEngine, and the TH prop and PJN may actually be about the same, near the 1.05 mark. The Falcon electric beech looks like 1.03 now with the three new ones I bought, while the gas version stays at 1.15. The problem I've had with beechwood is that the weighs are all over the place. I also wanted to bring the Lam Xoar pK down a bit and may do that when this is all over. It looks like it may drop again for the Lam.

 

[Enterprise]

Playing with the calculator I think the 21x10 will be a more appropriate prop for the A60-8S. The 22x10 pushes it to over 4000 watts in and 90A. Considering I am shaving a pound of that 13.6 weight with less motor and batteries I think I will be OK. A little over 2:1 thrust to weight with pretty decent flight times. It will be a little lighter than my 13 pound gasser 78 Extra spinning a similar diameter prop with more pitch and a few hundred more RPM compared to the VVRC 40, Mej 21x8 combo I am currently using.

Seeing that you are getting very similar numbers on the 24x10TH that we currently get with a DA-60/RE2 I would like to do a weight comparison.

Motrolfly 5335 is just over 1000 grams.
Castle 160HV ESC, 233 grams with wires
Gens Ace 6s 5300 x2 = 1504 grams.
BEC pro, 40 grams with wires

close to 2.8 kgs installed or 6.17 pounds

DA-60, 1410 grams
RE2 with header is very close to 1 pound last time I weighed it. (454 grams)
IBEC, .6 ounces or 17 grams according to specs
16 ounce fuel tank with fuel and lines I would guess around 20 ounces (567 grams)
RX batteries, 224 grams total
throttle servo, 70 grams with pushrod.

2.74 kg total or 6.04 pounds

DA-70 might be slightly lighter. The motor weights 7 ounces more, but you don't need the RE2 and header and those jtec mufflers are not very heavy. The DA-60 weight from the website may or may not contain the ignition module.

I find this pretty interesting in the fact that the Motrolfly is pretty close as the Q80 setup I had before with the emcotec safety switch was heavier than the gas setup. The big difference is as always flight times.

 

[gyro]

Not going to get mine into the air today, but since Pontus will be by this afternoon for a quick visit during a business trip, we're going to do some static tests and get some data points.

 

[Aeroplayin]

Matching apples to apples from the great data TimmyC provided.... this requires about a minute warm-up between 1/4 and 1/2 throttle, and then a 30 second WOT blast. I added a graph to the data parser that used the same formulas as I used to build the PropEngine and here are the result that span that WOT period for each setup.

 

[Aeroplayin]

Forgot to mention that the the image name contains the prop used, and the Glacier is a 30C and the Dino is supposed to be a 65C. All batteries have only a few cycles through them. This is all on the DM5335-189Kv.

 

[gyro]

Pontus and I just got finished with our run. 24x10TH Mej, Glacier 2x 6s5000 45C packs.

We warmed the motor and battery up for about 1.5 minutes, mixed throttle from low to med-high, bursts, etc.

Starting approximately 2 minutes in, we began the run:

10 sec - 117.3A, 43.1v, 5055w
20 sec - 114.2A, 42.7v, 4880w
30 sec - 113.8A, 42.5v, 4836w

Let it rest and recover for about 1 minute, then did it again:

10 sec - 122.3A, 43.3v, 5300w
20 sec - 119.8A, 42.5v, 5080w
30 sec - 115.1A, 42.2v, 4900w

RPM data was taken using hand held prop tach, and wasn't recorded.

First run peaked 6400, settled at 6250 for the remainder.

Second run peaked 6500, settled at 6340 for the remainder.

I personally don't have a ton of confidence in the little hand held RPM thing, but they're probably in the ballpark.

----

Also, it seems the numbers taken with the 24x9 Xion were skewed as a result of the prop being horribly out of balance. As a matter of fact, even adding a servo clip to the tip of one blade wouldn't balance it.



Hope this all helps.

Also, motor temp 3 minutes after this abuse was a comfy 141F peak, OAT 58F.

 

[Enterprise]

You can add RPM telemetry to your setup if you choose to. I have one that I use in my 60 laser.

http://www.horizonhobby.com/products/aircraft-telemetry-brushless-rpm-sensor-SPMA9558

I wonder if you can mod the hobbywing sensor to do this as it is a bit cheaper. I am using it in my heli for the Ikon governor.

 

[Buick Mackane]

I just wanted to thank everyone involved with this experiment and for all of the time you spent to collect this data. There must have been many hours spent to achieve this in-depth study. I'm expecting a 50cc Extra from Redwing and am planning an electric set-up. This info is a great help and much appreciated. GREAT JOB!